1. Field of the Invention
The present invention relates to an organic positive temperature coefficient thermistor having a PTC positive Temperature Coefficient) characteristic such that the resistance value increases drastically with increasing temperature.
2. Related Background Art
Thermoplastic resins are widely known as matrix materials for thermistor elements used in organic positive temperature coefficient thermistors. However, because thermoplastic resins require crosslinking treatment and noncombustible treatment to achieve heat resistance, the production steps for such thermistor elements are complex. As a result, attention has shifted toward thermosetting resins as matrix materials which can simplify the production process by eliminating such treatment.
Examples of hitherto studied organic positive temperature coefficient thermistors employing thermosetting resins which have been disclosed include types wherein a fibrous conductive substance is dispersed in a thermosetting resin (for example, U.S. Pat. No. 4,966,729), types wherein conductive particles with spike-like protrusions are dispersed in a thermosetting resin (for example, Japanese Patent Publication No. 3101047), and types wherein conductive particles with spike-like protrusions and conductive staple fibers are dispersed in a thermosetting resin (for example, Japanese Patent Publication No. 3101048).